In the processing of substrates, such as semiconductor wafers, a substrate is placed on a substrate support in a process chamber of a substrate processing system. The support for the substrate is often a support member, such as a heater pedestal, to hold the substrate in proper position during the processes performed. Typically, the substrate is placed on the support member and generally centered with respect to the support member for the substrate to be processed uniformly. One or more processes, such as plasma processes or other processes, are then carried out on the substrate. After completion of the one or more processes, the substrate is then removed from the substrate support, for example, using lift pins that may be displaceable in a direction perpendicular to the plane of the substrate support. The lift pins move relative to the substrate to lift the substrate off of the substrate support for subsequent removal of the substrate from the process chamber.
The inventors have observed that, in some processes, the substrate may undesirably move on the substrate support when attempting to lift the substrate after completion of the process. Specifically, the inventors have observed that the substrate may undesirably move upon attempting to lift the substrate after completion of some processes carried out on a substrate having a thick back oxide layer (such as a thickness of about 10 kA or more) disposed on a substrate support with the back oxide layer contacting the substrate support.
Accordingly, the inventors have provided embodiments of improved methods and apparatus for processing substrates in a process chamber.